The potash slat ore such as carnallite produces tailing and tail liquid during common mineral floatation process, wherein more than 90% of the tailing is NaCl, and the tailing is normally piled up in a tailing pond or dryly filled into a goaf. The main ingredients of the tail liquid are 22% to 25% of MgCl2, 3.3% to 4.4% of KCl and 1.8% to 3.3% of NaCl. The tail liquid is normally used for recycling carnallite by concentration or is directly discharged to outside. Until now, there is not an economic and effective method for treating the carnallite tail liquid at home and abroad yet.
During a stowing process in an ordinary mine, a silicate cement is generally used as a cement material for mixing with the tailings to prepare filling slurry for stowing. Traditional stowing methods may not be suitable for the goaf of potash salt ore, because a recovery in a goaf of potash salt ore usually has a strict requirement on the strength of stowing. Being affected by the chloridion, the solidification strength of silicate cement is greatly reduced after being solidified, along with its cost that is too high, so it is unable to meet the stowing requirements.
With respect to a goaf of potash salt ore, there are currently a lot of stowing methods, such as a stowing method for a goaf disclosed in CN 101864989A, which mixes tailings, magnesium cement and coal ash to prepare filling slurry to be transferred to a goaf. CN 101864988A discloses a stowing method for a goaf of potash salt ore, which mixes tailings and magnesium cement to prepare filling slurry to be transferred to a goaf. The above methods all utilize a single filling slurry, the stowing strength is not easy to be controlled, and the cost for stowing is too high; moreover, only the tailing is treated while the tail liquid is not effectively utilized, and the discharge of tail liquid results in a great environmental pressure.